Rocket chamber and method of making

ABSTRACT

A transpiration cooled rocket chamber is made by forming a porous metal wall on a suitably shaped mandrel. The porous wall may be made of sintered powdered metal, metal fibers sintered on the mandrel or wires woven onto the mandrel and then sintered to bond the interfaces of the wires. Intersecting annular and longitudinal ribs are then electroformed on the porous wall. An interchamber wall having orifices therein is then electroformed over the annular and longitudinal ribs. Parallel longitudinal ribs are then formed on the outside surface of the interchamber wall after which an annular jacket is electroformed over the parallel ribs to form distribution passages therewith. A feed manifold communicating with the distribution passages may be fabricated and welded to the rocket chamber or the feed manifold may be electroformed in place.

United States Patent 11 1 Fortini 1 Oct. 7, 1975 [5 ROCKET CHAMBER ANDMETHOD OF 3,692,637 9/1972 Dederra et al 60/267 x MAKING OTHERPUBLICATIONS [75] Inventor: Anthmy Forum Cleveland Ohlo Barrere et al,,Rocket Propulsion, Elsevier Pub. [73] Assignee: The United States ofAmerica as w London, 1960; P-

represented by the United States National Aeronautics and Space PrimaryExaminer-C, J. Husar Administration, Washington, DC. AssistantExaminerRobert E. Garrett Filed: Jan 1974 fifilrrgyidllgnegggor Fzrm N.T. Musial, .l. A. Mackm, [21] Appl. No.: 436,316

Related U.S. Application Data [57] ABSTRACT [62] Division of Ser. No.289,050, Sept. 14, 1972, Pat. A transpiration Cooled rocket Chamber ismade y No. 3,832,920, forming a porous metal wall on a suitably shapedmandrel. The porous wall may be made of sintered pow- [52] U.S. Cl.60/265; 60/267; 239/1273 dered metal, metal fibers sintered on themandrel or [51] Int. Cl? F02K 9/02; FO2K 11/02 wires woven onto themandrel and then sintered to [58] Field of Search 60/265, 267, 39.66,DIG. 8; bond the interfaces of the wires. intersecting annular239/127.l, 127.3 and longitudinal ribs are then electroformed on theporous wall. An interchamlber wall having orifices [56] References Citedtherein is then electroformed over the annular and UNITED STATES PATENTSlongitudinal ribs. Parallel longitudinal ribs are then 2,183,313 12/1939Goddard 60/265 x fmmed outs'de merchamber 2,518,881 8/1950 Goddard60/265 X wall after which an annular acket 1s electroformed 2,941,7596/1960 Rice etal 60/39.66 the Parallel ribs to form distributiO"Passages 2975590 3/1961 yonder 60/39 66 X therewith. A feed manifoldcommunicating with the 3,067,982 12/1962 Wheeler 416/231 distributionpassages may be fabricated and welded to 3,069,847 12/1962 Vest 60/265the rocket chamber or the feed manifold may be elec- 3,349,558 10/1967Smith 60/39.66 X {roformed in place 3,613,778 10/1971 Feldman 165/1053,656,863 4/1972 De Feo 416/231 1 Claim, 2 Drawing Figures US. PatentOct. 7,1975

ROCKET CHAMBER AND METHOD OF MAKING ORIGIN OF THE INVENTION Thisinvention was made by an employee of the United States Government andmay be manufactured and used by or for the Government for governmentalpurposes without the payment of any royalties thereon or therefor.

This is a division of application Ser. No. 289,050 filed Sept. 14, 1972,now US. Pat. No. 3,832,920.

BACKGROUND OF THE INVENTION The invention relates to transpirationallycooled rocket chambers and is directed more particularly to an improvedrocket chamber and a method for making such a rocket chamber.

A transpirationally cooled rocket chamber is one in which the inner wallmay be either a porous material such as a ceramic or metal or a wallhaving numerous apertures no larger than about 250 microns each in size.The pores of apertures of these walls allow passage of a transpirantthereby cooling the wall as it exits toward the combustion side and thusprotecting the porous wall from destruction. To distribute the coolantover the porous wall distribution channels and manifolds must beprovided.

In the past, transpirationally cooled rocket chambers have beenassembled by stacking grooved plates. Such an arrangement is difficultto assemble, is very costly, and is excessive in weight, particularly insituations such as a space vehicle where weight is a critical factor.Additionally, in the past, the coolant or transpirant liquid supplychannels were attached to the porous inner wall by means of brazing,welding or diffusion bonding. All these methods result in blockingsubstantial areas of the porous walls as well as causing distortions inthe rocket chamber which undesirably effect the relatively precisedimensions and positioning required for the structural components whichcontrol the transpirant flow.

Attempts have also been made to fabricate transpirationally cooledrocket chambers from elongated staves similar to the way a wooden barrelis assembled. Each stave comprised a porous inner wall and the necessarypassageways and outer walls. The staves were then assembled to form anannular rocket chamber. Then the staves were welded, brazed or diffusionbonded together. This method again resulted in excessive blockage of theporous wall whereby passage of the transpirant was substantially reducedso that adequate cooling of the inner rocket chamber wall was notprovided.

OBJECTS AND SUMMARY OF THE INVENTION It is an object of the invention toprovide a transpirationally cooled rocket chamber which is relativelylightweight and inexpensive to construct.

It is another object of the invention to provide a rocket chamberwherein the permeability of an inner porous wall is continuous andvaries in a predetermined manner even in areas where components arebonded to the porous wall.

Still another object of the invention is to provide a rocket engineconstruction method which is simple and easy to perform and whichprovides for accurate positioning and configuration of the variouscomponents making up the rocket chamber.

It is yet another object of the invention to provide a rocket engineconstruction method wherein no welding, brazing or the like is requiredthus avoiding damage and blockage to an inner porous wall.

A further object of the invention is to provide a rocket engineconstruction method which can be accomplished without distorting thecomponents making up the rocket engine.

In summary, it is an object of the invention to provide atranspirationally cooled rocket engine requiring no welding, diffusionbonding, or brazing by starting with a precisely shaped porous wall withfixed permeability and then electroforming the required components.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a pictorial oblique view,partially cut away, of a longitudinal section of an annular rocketchamber embodying the invention. a

FIG. 2 is a partial traverse section taken along the line 2-2 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 there isshown a partially cut away oblique view of a portion of a rocket chamberembodying the invention. The rocket chamber has a porous inner wall 11having the desired shape, permeability and configuration of a rocketchamber. The wall 11 may be made by wrapping or weaving a fine wirecloth or matrix on a suitably shaped mandrel. The wire cloth may be madeof stainless steel, copper or bronze wires although other wire materialsmay be used depending upon the temperature range of operation of therocket chamber. After the: wire cloth is positioned on the mandrel, itis sintered. to provide a tenacious bond at any point where one wirecontacts another.

The inner wall 11 may also use other kinds of porous media made ofstainless-steel, copper or bronze formed and sintered over a suitablemandrel. For example, pads of metal wool (similar to steel wool) may bearranged on the mandrel and then sintered. Another alternative is to usea solid metal which may be made po' rous by acid etch techniques orusing a laser beam.

The inner wall 11 is coated with a soluble material such as wax orplastic. By soluble materials is meant ones that may be easily removedfrom passageways, openings and the like. Wax, for example, may beremoved by heat or the passage of hot liquid while plastic may bedisoolved by acetone. Longitudinal and annular grooves are then cut inthe wax corresponding in pattern to the longitudinal and annular ribs 12and 13. These grooves are then filled with metal by electroformingtechniques which are known to those skilled in the art to form thelongitudinal and annular ribs 12 and 13 which are tenaciously bonded tothe porous wall 11. The spacing between any adjacent pair of annularribs 13 and longitudinal ribs 12 forms distribution cavities 14 whichreceive a coolant from passages as will be described presently and whichis to be expelled through the porous wall 1 l to effect cooling theporous wall 1 1.

To form an inter chamber wall 15, the ribs 12, 13 are smoothed bymachining or the like and then cleaned. The inter chamber wall 15 isthen electroformed over the ribs and makes a tenacious bond at allpoints of contact with the ribs.

To the end that coolant pressure in each of the distribution cavities 14will be substantially distributed as required for cooling the porouswall 11, metering holes 16 are drilled in the inter chamber wall 15. Inlieu of drilling, suitable soluble rods may be disposed in a radialrelation to the rocket chamber in each of the distribution cavities 14.

Distribution manifolds 17 are established by longitudinal ribs 18 whichextend along the rocket chamber between rows of metering holes 16 to theexhaust nozzle end of the rocket chamber which is closed by a wall 19which is also electroformed. The ribs 18 do not extend all the way tothe front end 20 of the rocket chamber to provide for entrance ofcooling fluid as will be described presently.

The ribs 18 are tenaciously bonded to the inter chamber wall byelectrodepositing metal in grooves which have been cut in a wax orplastic layer deposited over the inter chamber wall 15. The ribs 18 arethen machined smooth and cleaned. An outer jacket 21 is thenelectroformed over the ribs 18 and bonded to them. Finally, an annulardistribution channel 22 is attached to the front end of the rocketchamber, the manifold 22 having walls which may be welded to the jacket21 or the front end of the chamber 20.

The distribution manifold 22 and the front end 20 may also beelectroformed in place, as shown in FIG. 1, to avoid welding.

After the rocket chamber is completed, the soluble material is removedfrom the interior passageways, channels and orifices by either heat, hotliquid, acetone or the like, depending on what soluble material wasused.

FIG. 2 is a traverse section of a portion of the rocket chamberembodying the invention as shown in FIG. 1 and like parts are identifiedby like numerals. Shown in FIG. 2 are the porous wall 11, thelongitudinal ribs 12, the inter chamber wall 15, the distributionmanifold 17, the longitudinal ribs 18, the jacket 21, and thedistribution cavities 14.

The permeability or ability of the porous wall to pass transpirant isnot blocked or reduced by the ribs bonded thereto. From FIG. 2, it willbe seen that, be-

cause of the thickness of porous wall 11, transpirant will flowlaterally around the ribs and through the areas directly under the ribs.

It will be understood that some areas of the rocket chamber, the throatfor example, will require more cooling than other areas. The desiredtranspirant flow is obtained by providing areas of different porosityand permeability for the wall 11 and/or by using metering holes ofdifferent size at various points in said inter chamber wall 15. Thus inthe throat area of the rocket more transpirant flow may be obtained byproviding increased porosity in the wall 11 and/or by increasing themetering hole size.

It will be understood that changes and modifications may be made to theforegoing invention without departing from the spirit and scope as setforth in the claims appended hereto.

What is claimed is:

1. A rocket chamber comprising:

an inner annular wall of porous material, wherein said inner annularwall is tightly woven wire bonded at points of contact, said wire beingselected from the group of metals consisting of stainless steel, bronzeand copper;

a network of annular and longitudinal ribs disposed outwardly of saidwall and bonded thereto;

an interchambe r wall disposed outwardly of said ribs and bonded theretoto form distribution cavities, at

. least one metering orifice being located in said interchamber wall atevery distribution cavity,

a plurality of parallel longitudinal ribs disposed outwardly of saidinter chamber wall and bonded thereto;

an outer annular jacket bonded to said longitudinal ribs and definingwith said longitudinal ribs and said inter chamber wall a plurality ofdistribution manifolds; and

a feed manifold bonded to the front of said rocket chamber andcommunicating with said distribution manifolds.

1. A rocket chamber comprising: an inner annular wall of porous material, wherein said inner annular wall is tightly woven wire bonded at points of contact, said wire being selected from the group of metals consisting of stainless steel, bronze and copper; a network of annular and longitudinal ribs disposed outwardly of said wall and bonded thereto; an interchamber wall disposed outwardly of said ribs and bonded thereto to form distribution cavities, at least one metering orifice being located in said interchamber wall at every distribution cavity, a plurality of parallel longitudinal ribs disposed outwardly of said inter chamber wall and bonded thereto; an outer annular jacket bonded to said longitudinal ribs and defining with said longitudinal ribs and said inter chamber wAll a plurality of distribution manifolds; and a feed manifold bonded to the front of said rocket chamber and communicating with said distribution manifolds. 